The present invention pertains to a control unit for setting heating, cooling and/or ventilation systems in motor vehicles and in particular, such control units containing a sliding member with a control lever which is guided between two end positions and which actuates setting members.
The control units of this kind, which are arranged on the instrument panels of motor vehicles, are used for opening to variable extents distribution louvers of cool or warm air vents in motor vehicle systems, and are often called heating-cooling systems. The vents or other members are usually actuated via Bowden cables.
A Bowden cable is also provided in the control unit which is described in DE-OS No. 31 25 093. This control unit consists of an oblong body with a canal provided within it, and a sliding member in the canal which can be slid between two end positions. The sliding member is guided in the canal by rollers attached to it, which rest against the canal walls. Projecting in different directions, a control lever projecting from the body and an adjusting arm are provided on the sliding member. The Bowden cable is operated by means of the adjusting arm, and this adjusting arm is also a switching means carrying a contact bridge which cooperates with fixed contacts of the body in the manner of a sliding switch.
Another control unit for a heating and cooling fan of a motor vehicle is known from DE-GM No. 83 12 000. A part of a handwheel which is held rotatably in a body projects from the instrument panel. A pinion is molded onto the handwheel. The teeth of the pinion mesh with the teeth of a gear which in turn meshes with the teeth of a toothed rack. The toothed rack is held in a guide of the body in a longitudinally movable manner. A plurality of contacts located in rows next to each other are actuated by a cam provided on the toothed rack as the toothed rack is slid to different stop positions. The fan motor is thus switched on and off stepwise. A display unit which is visible from the outside through a transparent zone of the instrument panel is connected with the toothed rack.
Since the sliding members of the heating and ventilation control units of motor vehicles reach through slots, the inner mechanism becomes easily contaminated. Also, foreign light is often emitted through the slot in the case of illuminated control units. To avoid this, it was proposed in DE-OS No. 32 11 319 to cover the slot by a tape which is attached to the sliding member. The ends of the tape can be open or an endless tape can be used. The tape itself is guided in an opening on both sides of the slot between a body and a cover plate.
Another control unit with illuminated control knobs was described in DE-OS No. 32 06 288. There are one or more than one sliding members which are guided in slots of the body. Via an intermediate lever the sliding member actuates an adjusting lever to which is attached a Bowden cable. The control knobs mounted on the sliding members on the outside are illuminated by mobile light guides. The light guides emanate from a light source and are led in the middle through the sliding member and to the control knob.
An illuminated display of the actual operating position of the sliding members is provided in the control unit disclosed in DE-AS No. 15 80 098. The sliding members are led in slots of a body, and the pins projecting from other slots transmit the sliding motion of the sliding members via lever bars to actuators, which in turn move the Bowden cables. Luminous strips which extend over the entire adjustment range of every individual sliding member are provided on the front side of the body. They are visible from the outside as a light band. Each luminous strip is illuminated via a frame part prepared from transparent plastic, which collects the rays and sends them to the light guides. To better visualize the start and end positions of the sliding member the luminous strip is wedge-shaped at the front end. Colored illumination can also be provided. However, it is not apparent from this publication how this is to be done.
Another control unit for motor vehicles, in which the control knobs of the sliding members are illuminated, is known from DE-GM No. 76 34 978. The sliding members are guided in slots of the body. The light necessary to illuminate the control knobs reaches the control knobs from a central light source after deflections via light carrier arms or light guides. On the light transmission surfaces the light guides are corrugated so that a diffusely illuminated surface is obtained. The light guides are prepared from polymethacrylate by injection molding. The central light source is inserted into an opening of a block from which the light guides are led out. A light-emitting diode which is able to emit white as well as colored light, is used as the light source.
A light guide bar for colored illumination of instruments in motor vehicles is described in DE-GM No. 80 04 562. A colored layer with a thickness of 30 microns is applied on the reflecting surface of the light guide bar. This colored layer is topped by a second, white layer. A separate light guide bar is used for each color. It is not possible with this solution to illuminate two different colored surfaces one after another with the same light guide bar.